The FreshWater III Corona Discharge Ozone System is included on every Hot Spring HighLife hot tub. Ozone is a very powerful “contact” sanitizer. This means when ozone is created and injected into the water stream, it kills the bacteria in the water. When it is injected continuously (which is the case wheh your spa has a 24 hour circulation pump), then you are killing bacteria continuously. Ozone systems can be added to almost every hot tub.